A. Field of the Invention
The device of the present invention relates to a new and improved contactless pressure switch that is sensitive to fluid pressure rates of change.
B. Description of the Prior Art
Pressure control switches whether employed in closed systems or systems in communication with the atmosphere typically employ contacts, which over the normal operating life become contaminated or deteriorate due to the atmosphere to which they are exposed thereby requiring costly replacement or repair. Pressure switches used in sensitive edges or doors for transit vehicles such as the type illustrated and described in U.S. Pat. No. 4,133,365 utilize electric contacts as indicated above, along with an additional modification of a switch diaphragm rendering this switch rate sensitive, or responsive to pneumatic pressure waves or pulses. Prior art pressure sensitive switches are actuated by continuous pressure and only remain engaged as long as the pressure is maintained.
The prior art switches discussed above are unsatisfactory due to unreliable contact operation.